What is Cardboard & How is it Made? Strength, Grades & Beyond!

A stack of three flat, rectangular pieces of cardboard on a surface. Text above the cardboard reads "WHAT IS CARDBOARD?
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Some things are so commonly used in our daily lives that we barely notice their significance. One such thing is cardboard, which combines strength, lightweight properties, and versatility in a way that makes it indispensable.

From packaging and storage to creative projects, cardboard’s presence is ubiquitous. Its ability to effectively protect stored items from damage, coupled with its durability, has made it a top choice for businesses across various industries.

Do you want to know more about cardboard in detail? Let’s dive more in-depth into what makes cardboard so essential and how it impacts our world.

What is cardboard composed of?

Composed of paper pulp, cardboard is sourced from either pure pulp or reused fibers via a pulping process. This wood pulp is processed and communed into bland sheets, which can then be transformed into cardboard products like corrugated cardboard and paperboard.

Corrugated cardboard is created by sandwiching flutes between two layers of paperboard. This process is known as corrugation. To meet various packaging needs, it can be produced in various thicknesses, colors, and textures.

Manufacturing Process

The packaging production process has several important steps to convert the raw materials into the versatile material cardboard. Let us break down each production step in detail for a clearer understanding.

Pulping

The first step in making cardboard is pulping in which the collected raw materials are broken down into a fibrous pulp.

There are two methods to achieve this:

  1. Mechanical pulping involves grinding the wood into fibers.
  2. Chemical pulping uses chemicals to separate the fibers.

Cleaning Raw Materials

This step aims to remove residual impurities such as bark, dirt, or ink residues. It ensures a high level of purity that forms the basis for high-quality cardboard production.

Bleaching

This step helps in gaining a consistent, uniform white color. It is performed by bleaching the pulp. It removes any remaining tints from the source materials. 

Forming

With the help of a machine known as a Fourdrinier machine, the pulp is transformed into flat sheets. The pulp is poured on a flat surface for draining to form a layer of pulp.

Pressing

After the pulp sheets are formed, they undergo a pressing process as they pass through large rollers.

Corrugation

The flat sheets of cardboard then go through a corrugator machine to add strength and durability. Corrugation means putting wavy flutes between two sheets, giving it a unique pattern. Corrugated cardboard is strong and popular for safely shipping items and preventing damage during transportation.

Cutting and shaping Cardboard

This step allows to make many different things from cardboard sheets. Boxes, containers, and other items are carefully created using cutting and shaping methods.

Grades of cardboard

Cardboard grades are categorized based on the percentage of recycled fiber they contain. All grades are recyclable. Here are the different types:

  • Kraft (K): It is created from pure fibers that have never been recycled before.
  • Chip (C): Consists of 100% waste-based liners.
  • Bleached White (BW): Features a bleached Kraft liner made from pristine fibers.
  • White Top (WT): Made from recycled fibers with a white coated liner.
  • Mottled Kraft (MK): Uses a blend of virgin and recycled fibers.
  • Oyster (OY): It is made by combining pure and reused fibers.
  • Semi-Chem (SC): Utilizes a neutral sulfite semi-chemical process with virgin fibers, 

often used for fluting.

  • Waste-Based (WB): Composed entirely of 100% reclaimed paper fibers, commonly used for fluting.

Only wax-coated or contaminated cardboard, such as by food or other substances cannot be compacted or recycled.

Benefits of Choosing Cardboard

The versatility of cardboard makes it useful in a broader way.

  • Packaging and Shipping: Cardboard boxes are ideal for packaging and shipping goods due to their strength, lightweight nature, and cost-effectiveness. They provide ultimate protection and are easy to stack and transport.
  • Storage: Cardboard storage boxes are widely used in homes and businesses for organizing and storing items. They come in diverse sizes and designs to suit different storage needs.
  • Customized Packaging: In packaging, cardboard is a preferred material due to its versatility in easy cutting, folding, and painting, making it ideal for various artistic projects.
  • Cost-Effective Choice: From a cost perspective, cardboard is an excellent option for individuals and businesses who seek an affordable packaging solution.
  • Recyclable: Cardboard is generally considered an environmentally friendly material due to its recyclability and biodegradability. This makes it a popular choice among eco-conscious customers.

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